The major purposes of this Vector Core unit in this IP/CP application are to provide the needed quantities of purified, characterized rSV40 viral vectors to the projects in this consortium group. Accordingly, the Vector core will generate SV40-derivative viruses for use by the PPG group. These viruses will be produced in the necessary quantities, and then band- purified and quantitated by in situ PCR titering. In addition, the Vector Core will assess the quality of virus preparations produced. The ability of each preparation to express its transgene will be ascertained. Microbiological quality control for the preparations will also be ascertained: freedom from bacterial, fungal, mycoplasma, and other microorganism contaminants will be maintained. Lack of contamination by replication-competent SV40 revertants will also be ascertained. Finally, this Vector Core unit will evaluate the l4evels of serum antibody capable of neutralizing SV40 as well. For these examinations, projects involving administration of rSV40 vectors to animals will collect sera and subunit them to the Vector Core may be suitable for vector production for Phase I human studies, should these be authorized during the course of this project. Thus, this Vector Core facility will provide titered, and characterized rSV40 virus vectors to the individual project investigators. The Vector Core will provide the viruses in quantity and at sufficient purity to be used for animals (and, when necessary, human) studies, and will test for antibody responses against virus antigens.